Filibuster War

The Filibuster War was fought from 1856 to 1857 when a coalition of Central American armies launched a campaign to remove the American filibuster William Walker from power in Nicaragua. Walker, a lawyer from California, was hired by the Liberal Party of Nicaragua to bring a mercenary corps to help them defeat the rival Conservative Party of Nicaragua in a civil war, but Walker and his men eventually seized power and attempted to turn Nicaragua into a future slave state of the United States. Walker and his men lacked the support from the USA which they desired, and the Central American coalition ultimately defeated Walker and forced him to surrender to the US Navy, having violated the USA's neutrality laws.

Background
In 1854, a civil war erupted in Nicaragua between the Conservative Party and the Liberal Party, and the Liberals sought support from the famed American filibuster William Walker. President Francisco Castellon gave Walker a contract to bring 300 "colonists" to Nicaragua to help him circumvent the USA's neutrality laws, and Walker left San Francisco, California with 60 men on 3 May 1855. Upon landing in Nicaragua, the force was reinforced by 170 locals and 1000 Americans. With Castellon's consent, Walker attacked the Conservatives in the town of Rivas, and he was driven off, although he inflicted heavy casualties. On 4 September, however, Walker defeated the Conservatives at La Virgen, and he conquered their capital of Granada on 13 October. Walker became commander-in-chief of the Liberal army, and Patricio Rivas became Walker's puppet president. US president Franklin Pierce recognized Walker's government on 20 May 1856.

War
Walker, who had intended to turn Nicaragua into a slave state of the USA, made plans to conquer other parts of Central America. Nicaragua's Central American neighbors were scared by Walker's expansionist plans, and President of Costa Rica Juan Rafael Mora declared war on Walker's government. Walker responded by launching a preemptive invasion of Costa Rica, but they were defeated at Santa Rosa in March 1856. In April 1856, Costa Rican forces invaded Nicaragua and defeated Walker's army at the Second Battle of Rivas. On 12 July 1856, Walker took office as President after winning an uncontested election, and he launched an Americanization campaign of reinstating slavery (which had been abolished since 1821), declaring English an official language, and reorganizing currency and fiscal policy to encourage immigration from the USA. Meanwhile, the governments of Honduras, El Salvador, and Guatemala signed an alliance treaty on 18 July 1856, recognizing Patricio Rivas as the President of Nicaragua. Democratic and loyalist forces loyal to Rivas joined the alliance on 12 September 1856. On 14 September, the Central American army defeated Walker's forces at San Jacinto. By the end of 1856, Walker ordered the destruction of the Nicaraguan capital of Granada. At the same time, Walker was also sabotaged by the American businessman Cornelius Vanderbilt, who sent agents to help the Costa Rican army recover the Transit Company from Walker; the Costa Ricans captured all of Walker's steamships, weakening his army. By January 1857, the Costa Rican Army was in control of the San Juan River and the steamships. Walker was expelled from Granada by the allied armies, and his forces failed to regain control of the San Juan River. On 17 April, Central American troops occupied San Juan del Sur, and Walker briefly recaptured Rivas before being forced to retreat. Under pressure from the Costa Ricans, Walker ultimately surrendered to the US Navy on 1 May 1857 and was repatriated, and he received a hero's welcome in New York City. However, he alienated public opinion when he blamed his defeat on the US Navy, and he was executed by Honduras in 1860 after returning to Central America to help British settlers create a separatist island state.